Circuit arrangement for producing current impulses with very steep flanks

ABSTRACT

A circuit arrangement for the production of current impulses with very steep flanks, utilizing current impulses of an impressed current source, in which the current impulse source is connected to a voltage supply therefor with a time dependent voltage source, with the impulse current source being supplied at its load, during the initiation of an impulse, with the full operating voltage and thereafter for the remainder of the impulse with an operating voltage which covers only the circuit losses.

United States Patent Inventor Peter Elsner Munich, Germany Appl. No. 638,830 Filed May 16, 1967 Patented Feb. 16, 1971 Assignee Siemens Aktiengesellschaft Berlin and Munich, Priority May 25, 1966 Germany $103977 CIRCUIT ARRANGEMENT FOR PRODUCING CURRENT IMPULSES WITH VERY STEEP FLANKS 1 Claim, 5 Drawing Figs.

US. Cl. 307/263, 307/268, 307/270, 328/67, 340/174 Int. Cl 03k 5/12 Field of Search 307/263, 268, 270, 294, 282, 283; 328/67, 164, 172; 340/174 References Cited 1 UNITED STATES PATENTS 2,465,840 3/1949 Blumlein 307/268X 2,470,895 5/1949 Marlowe et a]. 328/226X 3,025,411 3/1962 Rumble 328/67X 3,200,308 8/1965 Mazgy 307/263X 3,440,628 4/1969 Vercellotti et al 307/282X 3,440,629 4/1969 VCI'CCIlOtti et al. 307/282X Primary Examiner-Donald D. Forrer Assistant Examiner-R. C. Woodbridge Attorney-Sherman, Meroni, Gross & Simpson CIRCUIT ARRANGEMENT FOR PRODUCING CURRENT IMPULSES WITH VERY STEEP FLANKS The invention relates to a circuit arrangement for producing current impulses with very steep flanks, utilizing current impulses of an impressed current source.

Such circuit arrangements are especially needed in rapid storers with magnetic cores which require high pulse currents with very steep flanks. Newly developed rapid storers with magnetic cores are characterized by very short signal paths and therewith by high packing densities of the switching devices. Due to heating these high packing densities require circuits with extremely low loss. Since in storers with magnetic cores the greatest part of the power loss is converted in the control switching network, a reduction of the minimum losses therein is necessaryv The control switching networks used to date operate either the invention;

FIG. 3 is a circuit diagram illustrating one embodiment of the invention; and

FIGS. 4 and S'are circuit diagrams illustrating'further embodiments of the invention.

In the example of the constant current feed of a circuit illustrated in FIG. I, there is provided a source of current impulses comprising a transistor T, and a'resistance R which is connected to a source of constant'current andhas a circuit L as a load which is short-circuited at the one end and terminated at the input end by its characteristic impedance Z. The voltage appearing at the input of the circuit, following the connection of the transistor, breaks down after. the double travel time and stands at the transistor 'I for the remaining duration of the impulse. In this way an unnecessarily great power loss is converted in the transistor.

The problem underlying the-invention is to produce circuit arrangements for the production of current pulses, for example, as used for the control of core storers, with retention of the desired flank steepness of the control impulse and achievement of a low power loss. This problem is solved in accordance with the invention by connecting the current impulse source to a voltage supply with a time dependently controlled voltage source, the current impulse source preferably being supplied with a full operating voltage only during the duration of initiation of an impulse in its load and is thereafter supplied for the residual duration of such impulse with an operating voltage covering merely the switching network losses. I

As indicated in FIG. 2, the load'circuit V is fed from a current source QI which in turn is supplied from a voltage source OU with an operating voltage adjusted to the requirements and which is dependent upon time. The high operating voltage U (see FIG. I), which is required only for the duration of the initiation of an impulse, is switched over in the steady state condition to a considerably smaller operating voltage. The

FIG. 2 is a block diagram illustrating the basic concept o following connection of the current impulse source is derived for the short duration of the initiation of an impulse from condenser C, which was previously charged through a resistance R2 to a high voltage U2. In the normal steady state condition, on the-other hand, the current impulse source Cl is supplied, through the diode D,, with the considerably lower voltage U l In cases in which the circuit is operated with a very small keying ratio, it is practical to replace the resistance R, by a switch S, as indicated in FIG. 3 by the broken lines.

FIG. 4 illustrates an embodiment in which the voltage necessary for the operation of the current impulse source Ql, for the duration of the initiation of an impulse, is derived through a switch S from the voltage source U In the steady state condition the switch S is switched off and the current impulse source QI is operated from the low voltage source U, which is sufficient to cover the losses. The switch S can feed directly into the point P or can be coupled by a transformer U or by a condenser.

In the embodiment illustrated in FIG. 5 the switch S is temporarily connected prior to the operative connection of the current impulse source QI. A 'transfonner ll transforms the low voltage U, to a high value and charges the condenser C therewith. When the charging procedure is terminated, the current impulse source QI is switched in, which is fed forthe duration of the impulse initiation from the condenser C as well as through the transformer Q, provided that the switch S, as illustrated in the circuit arrangement in FIG. 4, is not temporarily switched off until after the initiation of an impulse. This arrangement has the additional advantage that only a single voltage source is required, namely the low voltage U,.

The circuits indicated in FIGS. 3m 5 are common to the transistor T1 and the resistance R1, and comprise primarily the current impulse source QU, whose output currenti is approximately proportional to the input voltage on the base of the transistor, provided that the voltage at the point P applied by the voltage source QU issuffieiently large. The applied voltage at the point P has a high valve only for the short dura' tion of the initiation of an impulse. For the remaining part of the impulse duration the current impulse source 0] will be operated with the lower voltage Ul. Consequently the transformed power loss in the circuits will be kept very low. The lower limit of the voltage U1 is determined merely by the voltage drops in the semiconductors, across the resistance R], and the loss of the line or circuit L.

Changes may be made within the scope and spirit of the appended claims which define what is believed to be new and desired to have protected by Letters Patent.

I claim:

1. A circuit arrangement for the production of current impulses with very steep flanks, comprising a first switch, a load operatively connected to said first switch, and a voltage supply parallel with said first diode, a second diode, a transformer having a secondary winding connected in series circuit with said second diode, said series circuit being connected in parallel with said capacitor, and a second switch, said transformer having a primary winding connected between said voltage source and said second switch. 

1. A circuit arrangement for the production of current impulses with very steep flanks, comprising a first switch, a load operatively connected to said first switch, and a voltage supply connected to said first switch and including means for developing a first voltage during the initiation of a current impulse at said load, mEans for developing a second voltage having a value less than said first voltage during the remaining duration of the current impulse, a voltage source, said second voltage developing means including a first diode connected between said voltage source and said first switch, said first voltage developing means including a capacitor connected in parallel with said first diode, a second diode, a transformer having a secondary winding connected in series circuit with said second diode, said series circuit being connected in parallel with said capacitor, and a second switch, said transformer having a primary winding connected between said voltage source and said second switch. 